Margaret Hamilton, who led the team that wrote the onboard flight software for NASA’s Apollo program, leans into a mockup of the Apollo Command Module in this undated NASA photograph. Hamilton, who popularized the term “software engineer,” died on September 30 at age 90, and her priority-based design kept the Apollo 11 landing on track when the onboard computer overloaded. She is a fitting face for today’s word of the day, pioneer, and for a week of feature images about innovators. From NASA via Wikimedia Commons, public domain.